Systems which detect flaws in conductive materials by generating and detecting eddy currents in the materials being tested are well known in the art, being shown, for example, in Hochschild U.S. Pat. No. 2,877,406, Diamond et al U.S. Pat. No. 3,089,084 and Vild et al U.S. Pat. No. 4,123,708. While many of these devices readily test cylindrical articles such as methal rods or tubes, they are not readily adaptable for use with generally spherical articles such as bearing balls.